Hard metal composition



Patented Sept. 11, 1934 UNITED STATES PATENT oFFIcE 1,973,422 HARD METAL ooMPosrrioN 7 Elmer B. Welch, McKeesport, Pa, assignor to Firth-Sterling Steel Company, McKecsport, Pa., a corporation of Pennsylvania No Drawing. Application April 28, 1933,

Serial No. 668,386

6 Claims.

50% of the composition. The composition. of

the present invention differs from certain hard 10 metal compositions known heretofore and which contained a relatively large proportion of a hard metal carbide such as tungsten carbide and a relatively small proportion of an auxiliary metal such as cobalt, nickel or iron. In the composition of the present invention, the titanium carbide preferably constitutes only a minor proportion of the total composition, the metallic constituents, namely, the tungsten and aluminum, preferably constituting at least 50% of the composition.

The titanium carbide may vary between 15 and 60%, but preferably between 20 and 50%. In a preferred composition, it constitutes about 32%. The tungsten may vary between and 82%, but 25 preferably is between 40 and 74%. In a preferred composition, it constitutes about 60%. The aluminum may vary between 3 and 15%, preferably between 6 and 10%, and in a preferred composition it constitutes about 8% of the total composition.

The composition may be made bysintering, welding, fusing o melting the constituents. If a sintered compo tion is to be produced, titanium carbide, metallic tungsten,-and aluminum, all in finely powdered form, are. mixed together as by rolling them in a rolling barrel and are thereafter sintered at a temperature of about 3000 F. The mixed powders may be first compacted and then sintered, either with or without a prelimi- 40 nary sintering at a lower temperature, or the mixed powders may be compacted and sintered simultaneously in accordance with the hot press method. Where the mixture is first compacted and then sintered,,it is preferred to carry out the 5 sintering step in a hydrogen or other reducing atmosphere.

It has been found that cobalt, nickel or iron, w h are the auxiliary metals most commonly use in producing hard cemented carbide materials, have an embrittling effect if present in' my composition in amounts of 4 or 5% or more, or to some extent even when present in about 2% of. the composition. ,It is preferred, therefore, in my composition not to use these auxiliary metals, as or if they are present, to keep them below about 4 or 5%, and preferably below 2% of the composition.

My composition, wherein the titanium carbide preferably constitutes only a minor proportion of the composition, is easier to compress than compositions containing a relatively large amount of a hard metal carbide and a relatively small amount of auxiliary metal. The ease of compressing my composition facilitates its manufacture and the composition has less abrasive effect on the dies in which it is compressed than other compositions having a higher proportion of hard metal carbide. My preferred composition hasa Rockwell C hardness of about 78, which is approximately equal to the hardness of a composition containing about 94% of tungsten carbide and 6% of cobalt. My composition, containing a relatively small amount of titanium carbide, is more economical to produce than other compositions containing larger amounts of the carbide, and yet has proved to be an excellent steel cutting material.

The aluminum lowers the sintering temperature and, in addition, imparts hardness as well as age hardening propertiesto' the composition. A portion of the aluminum may be replaced by magnesium or beryllium in order to give increased hardness to the composition.

I have described the present preferred embodiment of my invention and have described one method of making the composition. It is to be understood, however, that the invention maybe otherwise embodied or practiced within the scope of the following claims.

I claim: I

1. A hard metal composition consisting of abou 15 to 60% of titanium carbide, about 25 to 82% of tungsten, and about 3 to 15% of aluminum.

2. A hard metal composition consisting of about 20 to 50% of titanium carbide, about'40 to 74% of tungsten, and about 3 to 15% of aluminum.

3. A hard metal composition consisting of about 15 to 60% of titanium carbide, about 25 to 82% of tungsten, and about 6 to 10% of aluminum.

4. A hard metal composition containing about 32% of titanium carbide, about 60% of tungsten, and about 3 to 15% of aluminum.

5. A sintered hard metal composition consisting of about 15 to 60% of titanium carbide, about 25 to 2'% of tungsten, and about 3 to 15% of aluminum.

6. A sintered hard metal composition consisting of about 20 to 50% of titanium carbide, about 40' to 74% of tungsten, and about 3 to 15% aluminumf Emma B. wrmcn. no 

